name=$('cat name')
while [ "$name" != "cosmos" ]
do
	dialog --inputbox "please input username" 10 30 2>name
	name=$(cat name)
done
	dialog --msgbox "welcome to student infor System" 10 20
while [ : ]
do
	dialog --menu "Choose your operation:" 10 40 4 1 "Add Student info" 2 "delete Student inofo" 3 "modify student information" 4 exit 2>menu.txt
	menu=$(cat menu.txt)
	dialog --msgbox "your choose is $menu" 10 20
	if ["$menu" -eq 4];then
		exit 0
	fi
done
